So-called “perma-cookies” give advertisers a solution to the problem of the largely cookie-free mobile Web—the data that’s tracked when people browse websites. Verizon calls the anonymous number used by advertisers to identify you a Unique Identifier Header or UIDH.
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Verizon’s partnerships for ad-tracking technologies were first revealed in May, but largely stayed under the radar until Electronic Frontier Foundation technologist Jacob Hoffman-Andrews tweeted about them last week.
“This is even at a more serious level than throttling traffic because ISPs are going in and modifying traffic in transit and that’s something that they should not be doing,” Hoffman-Andrews told Ars Technica. “They are paid by their customers to be trusted conduit for data, and they should be sending that data through faithfully rather than trying to insert or remove things.”
Opting out of the tracking is difficult, if not impossible. Verizon customers can opt-out of the Relevant Mobile Advertising program, but all that means is that Verizon won’t use the ID number to create targeted ads. But the tracking code in all your webpage requests (and those made by many of your apps) doesn't go away. Advertisers can still use those anonymous digits to create a profile of your mobile activity.
The only way to block the tracking code completely is to not use cellular data, instead relying on WiFi or a personal VPN.
